A Cross-site request forgery (CSRF) attack is a common threat to WordPress sites and can damage your website on multiple levels.
According to Patchstack, in 2023, Cross-Site Request Forgery (CSRF) constituted 16.9% of all new security vulnerabilities discovered in the WordPress ecosystem.
This attack allows hackers to gain access to admin accounts, extract sensitive information, delete user accounts, and, in some cases, steal money. If your website has CSRF vulnerabilities, attackers can also hijack authenticated user sessions to manipulate data, change settings, or cause widespread disruption.
But don’t worry! In this article, we will explain what a WordPress CSRF attack is and will show you the step-by-step process to prevent a WordPress CSRF attack.
What is a CSRF Attack in WordPress?
A Cross-Site Request Forgery (CSRF) attack is one of the most common WordPress attacks that tricks a user’s web browser into executing unwanted actions on a different site where the user is authenticated.
Still confused? Let’s break down the CSRF attack into three main parts.
- “Cross-site” refers to the involvement of multiple domains exchanging information.
- “Request” means the user’s browser is making a request to the web server. In technical terms, we call it “GET Request.”
- “Forgery” indicates the hacker is creating a fraudulent request to harm the user or the website.
This attack relies on the user’s active session with the target site. The hacker exploits this session to send malicious requests that appear legitimate because they originate from the authenticated user.
Therefore, a CSRF attack can lead to unauthorized actions, such as changing account settings, extracting sensitive information, or performing administrative tasks.
Example of a WordPress CSRF Attack
To understand the CSRF attack even better, check out the following example.
A user XYZ logs into their WordPress account on their site called “exampleforum.com.” Meanwhile, the user visits another site, “malicioussite.com,” where a hidden script runs. This script sends a request to “exampleforum.com” to change the user’s email address to one controlled by the hacker.
Because the user has already authenticated on “exampleforum.com,” the site processes the request by assuming that it is genuine.
As per this example:
- The “cross-site” aspect involves information exchange between different domains—in this case, exampleforum.com and malicioussite.com.
- The “request” part refers to the user’s browser making the forged request to the target site.
- The “forgery” occurs because the hacker creates a fraudulent request that appears to come from a legitimate user.
How Does a CSRF Attack Work in WordPress?
Let’s discuss the CSRF attack to see how it impacts a website. Below, we’ll clarify the concept and explain how it works.
Session Cookies
Session cookies are a key component in user authentication and session management on WordPress sites. When a user signs in, the server creates a unique session ID and stores it as a cookie in the user’s browser. This cookie is included in subsequent requests so that the server can recognize and maintain the user’s session.
However, just like Cookie Stealing or Session Hijacking attacks, a CSRF attack exploits this mechanism. Hackers trick users into making unintended requests that include these session cookies, allowing the malicious requests to be authenticated as if the legitimate user made them.
HTTPS Requests
HTTPS stands for Hypertext Transfer Protocol Secure. This encrypts data transferred between a user’s browser and the web server, which ensures the integrity and confidentiality of the information. This encryption is applicable to all users, whether logged in or not.
If a visitor is logged in, GET or POST requests are authenticated using session cookies. On the other hand, when a user is not logged in, the web browser doesn’t create any session, making CSRF attacks primarily a concern for authenticated sessions.
Two Sides of WordPress Site That Are Prone to CSRF
There are two sides to it: the user and the site. Let’s discuss how a CSRF attack affects them.
User Side:
Consider a scenario in which a user is signed into their WordPress site, “www.abc.com.” The hacker directs this user to another site, “www.xyz.com,” which could be achieved through a phishing email or a deceptive link.
Once on “www.xyz.com,” the user unknowingly clicks an image or button containing hidden HTML code that sends a request to “www.abc.com.”
Since the user has logged into “www.abc.com” with the same web browser, their session cookies are included in the request, making it appear legitimate to “www.abc.com.”
Website Side:
On the server side, “www.abc.com” receives the request and verifies the session cookies. Seeing the user as being logged in, the site processes the request without suspicion.
Unfortunately, this request contains malicious instructions, such as changing the user’s password. The hacker can then log in with the new credentials and gain unauthorized access to the user’s account.
This scenario becomes particularly troublesome if the compromised account has administrative privileges, allowing the attacker to take full control of the WordPress site.
Why is WordPress Vulnerable to CSRF Attacks?
In WordPress sites, vulnerable plugins are one of the main reasons for Cross-Site Request Forgery (CSRF) attacks. Many plugins have coding flaws that leave them exposed to these attacks. Developers might overlook security measures, or hackers may exploit advanced tactics to bypass defenses.
In 2020, the Wordfence threat intelligence team discovered a CSRF vulnerability in the popular WordPress plugin Code Snippet, which exposed more than 200,000 websites to the CSRF attack.
To mitigate CSRF attacks, plugin developers should implement two key security measures: nonces and anti-CSRF tokens.
- Nonces, or One-Time Tokens: They function similarly but have a short lifespan, often only a few minutes. They are generated dynamically when users perform actions like logging in or filling out forms. Because hackers cannot access these tokens, they can’t replicate them in their malicious requests.
- Anti-CSRF Tokens: An anti-CSRF token is a character string that is generated randomly by the server. Servers only accept requests when the correct token and cookies are present. Because hackers can’t access these tokens, any forged requests they try to make will be rejected by the server.
5 Easy Steps to Protect Against a WordPress CSRF Attack
By now, you’ve got a better understanding of how damaging a WordPress CSRF attack can be. Let’s see how to protect your WordPress site against such an attack.
Step #1: Secure Your Web Forms with Unique Nonces
Web forms are necessary for user interactions, like logging in, signing up, or making purchases. However, forms that do not include security against CSRF are susceptible to attacks. To secure custom forms, use nonces.
Add a nonce to your web form with the following code:
<form id=”test-form” method=”POST”>
<input name=”form_nonce” type=”hidden” value=”<?php echo wp_create_nonce(‘test-nonce’)?>” />
Then, verify the nonce with each POST request:
if (isset($_POST[‘form_nonce’]) && wp_verify_nonce($_POST[‘form_nonce’],’test-nonce’) && isset($_POST[‘new_email’]) && is_user_logged_in()) {
These steps will protect your WordPress site from most CSRF attacks.
Step #2: Remove All Unwanted Plugins & Themes
Plugins often expose your website to CSRF vulnerabilities. In general, the more third-party plugins or themes you have, the more potential entry points for hackers.
To minimize risks, uninstall any plugins or themes that you are not using. While themes are less commonly a security risk, it’s best to remove any unused ones to ensure maximum security.
Step #3: Exercise Caution with External Links
As a site admin, exercise caution when clicking on links. Avoid suspicious or unverified links, as they can lead to CSRF or phishing attacks.
Always verify the authenticity of the source before proceeding. It’s safer to type a URL directly into the address bar rather than clicking on a link. This habit can significantly reduce the risk of attacks.
Step #4: Implement Anti-CSRF Plugins for Enhanced Security
Forms like comment forms can be potential vulnerabilities. Use anti-CSRF plugins like the Comment Form CSRF plugin to secure them. This plugin adds a secret token to your forms that can be authenticated. To set it up:
- Go to your wp-admin panel and find the Comment Form CSRF plugin in the directory.
- Click “Install” when you find it.
- Once installed, click “Activate.”
This will automatically add tokens to your comment forms, enhancing their security without any additional steps.
Step #5: Automatically Log Out Inactive Users
CSRF attacks require the user to be logged in. By automatically logging out users who haven’t logged in for a while, you can prevent hackers from exploiting their accounts.
Websites and digital banks that handle sensitive information use this method. While it’s not a complete solution, it adds an extra layer of protection against CSRF attacks.
Final Thoughts on WordPress CSRF Attack
A CSRF attack can have a devastating effect on your WordPress site. This attack can lead to unauthorized access, data theft, and financial loss. Hackers exploit user sessions to perform malicious actions, which can compromise your website’s integrity.
To protect your WordPress site from CSRF attacks:
- Protect Custom Forms with Nonces
- Delete Unused Plugins and Themes
- Be Cautious About Clicking Links
- Use Anti-CSRF Plugins for Forms
- Log Out Users Automatically
Following these steps, you can safeguard your WordPress site against CSRF attacks and provide a secure environment for your users.
Lastly, If your website is targeted by a CSRF attack, consider using the Password Protected plugin. This plugin lets you restrict access to your site, which prevents new users from logging in until the problem is fixed.